No.
you cant get it without migrating.
you cant
You can get Poochyena into your Pokemon Diamond by migrating it from a Sapphire, Ruby, or Emerald Pokemon game.
yes.
use action replay
you can get a plusle in diamond by migrating it from like emerald or something like that
You Can keep playing the game but not with the Pokemon you migrated
No. Migrating is when u put a GBA Pokemon game in the GBA slot and get it in diamond thru the pal park. Trading u get a Pokemon from another trainer.
Near Hearthome city.
You can only get the petaya berry in Pokemon Colosseum, so the only way to get it on diamond is cheating or migrating.
YOU CAN'T GET CELEBI IN DIAMOND WITOUT MIGRATING
you can't get a celebi in Pokemon diamond, you only can get celebi by trading, migrating or by using action replay